The navy unit broke into the pod just before midnight, four days after the two activists began their occupation of the drilling platform of Leiv Eiriksson, an oil exploration vessel operated by the British firm Cairn Energy.

The arrests of Luke Jones, from Leeds, and Hannah McHardy, from the US, end a 10-day long action by Greenpeace and its protest ship Esperanza against Cairn's drilling operations off Greenland. The activists are now being held and are likely to be deported.

Ben Ayliffe, a Greenpeace International campaigner on board the Esperanza, said: "Our team stopped this rig from drilling for four days, which was four days in which a Deepwater Horizon-style blowout couldn't happen and this beautiful fragile environment was safe.

"Our climbers are in jail now, but this won't stop us opposing the madness of drilling for oil in a region where a spill would be almost impossible to clean up. This isn't over. We'll keep on pushing till the oil companies get out of the Arctic."

Cairn denies that its drilling operation was affected by the occupation. It and Greenland's government insist that its oil spill emergency plan is detailed and comprehensive, and argue that oil wells have been sited in the Arctic for several decades.